The development of tobacco-less smoking articles, such as those described in commonly assigned U.S. Pat. 4,966,171, required new automated methods and apparatus for high speed production assembly. The smoking article described in that patent includes a heat source and an air-permeable tube containing a granular material disposed adjacent to the heat source for generating a tobacco flavored aerosol.
One step in the assembly of that smoking article is to engage a measured amount or charge of aerosol-generating granular material from a bulk reservoir and to transfer that material to the air-permeable tube. Because the amount of granular material disposed in the tube must be maintained within precise ranges to achieve satisfactory performance, it is important that the methods and apparatus developed to accomplish this task work reliably and at high speed to facilitate automated operation.
Previously known devices for transferring charges of particulate matter from a bulk source to individual compartments are described in several prior art patents, for example, Molins, U.S. Pat. 3,570,557, Sexstone U.S. Pat. 3,844,200, and Washington et al., U.S. Pat. 4,005,668. All of these devices have in common the use of a rotating drum having a having slot or pocket through which suction is drawn to engage a charge of particulate matter from a reservoir. When the drum rotates, the slot or pocket registers with a target compartment, and the charge of particulate material is drawn into the target compartment using either suction applied at the base of the compartment or positive pressure applied to the charge of particulate matter to expel the charge of material into the target compartment. None of these previously known devices provides the capability to transfer precisely metered amounts of particulate matter to individual receptacles at target locations with high accuracy and at high speed.
In view of the foregoing, it is an object of the present invention to provide methods and apparatus for engaging a metered amount of granular material and for transferring that charge of granular material to a deposition site.
It is another object of this invention to provide methods and apparatus, suitable for high-speed automation, for disposing a metered amount or charge of granular material in a receptacle.
It is still another object of this invention to provide methods and apparatus for transferring a metered amount of granular material from a bulk reservoir to an individual receptacle with high accuracy and reliability.